This invention relates to a peroxyacid bleach composition in liquid form which is stable to decomposition of the peroxyacid compound during extended storage.
It is convenient and desirable to provide bleach compositions in liquid form. Peroxyacids, as a class, are desirable bleaches inasmuch as they do not weaken or react with dyed fabrics in the manner of harsh chlorine bleaches. However, most peroxyacids are solids, and it is very difficult to prepare stable liquid compositions containing peroxyacids as the active bleaching component. This difficulty is due in part to the inherently unstable nature of peroxyacids, which decompose at a rather rapid rate when placed in an aqueous medium or in a solution containing other materials in combination with the highly reactive peroxyacid compounds.
It is well-known that the tendency of peroxyacid compounds to decompose depends on such factors as temperature, pH, the presence or absence of water and the organic compounds which may come in contact with them. Moreover, contact with metal ions speeds decomposition. Small amounts of heavy metals catalytically cause liquid peroxyacid bleaches to decompose during storage and are therefore highly undesirable. Yet, the bleaching and cleansing action of peroxyacids is based on their ready decomposition, which yields minute bubbles of oxygen which penetrate cleanse and bleach materials such as textiles and clothing in an aqueous solution. However, the reactive nature of peroxyacids, which is so desirable in the cleansing and bleaching of fabrics during a laundering operation, presents special problems to the formulator upon storage of the bleach in liquid media.
Several methods have been utilized in the past to stabilize peroxyacid type compounds. For example, U.S. Pat. No. 3,192,254, Hayes, STABILIZATION OF PERACIDS WITH PICOLINIC ACID, issued June 29, 1965, relates to the stabilization of peracetic acid contained in a non-reactive organic solvent by means of picolinic and dipicolinic acids.
Another method of stabilizing peroxygen compounds is set forth in U.S. Pat. No. 3,192,255, Cann, STABILIZATION OF PERACETIC ACID WITH QUINALDIC ACID, issued June 29, 1965, which discloses a stabilized organic peroxide composition consisting of peracetic acid, an organic solvent and quinaldic acid.
U.S. Pat. No. 3,130,169, Blumbergs et al., STABILIZATION OF PEROXYCARBOXYLIC ACIDS, issued Apr. 21, 1964, teaches a process for stabilizing peroxycarboxylic acids which utilizes a solvent system composed of up to 80% of an organic saturated tertiary alcohol or mixture of tertiary alcohols. A preferred solvent system consists of tertiary butyl alcohol, either alone or in combination with tertiary amyl alcohol. Dipicolinic acid is additionally taught for use therein to complex heavy metal ions.
U.S. Pat. No. 3,661,789, Carey et al., STABILIZED OXYGEN BLEACH-ACTIVATOR SYSTEM, issued May 9, 1972, relates to an oxygen releasing bleach system which is said to be storage-stable. The reference discloses perborate bleaches, and bleach activators such as the heavy metal salts of transition metals, in combination with chelating agents such as picolinic acid and nonionic surfactants or glycols.
U.S. Pat. No. 3,388,069, Linder et al., LIQUID ACTIVE OXYGEN DETERGENT BLEACHING CONCENTRATE, issued June 11, 1968, relates to stabilized peroxygen compounds, hydrogen peroxide, and surfactant stabilizers.
U.S. Pat. No. 2,454,254, Knoch et al., STABILIZED ORGANIC PEROXIDES, issued Feb. 24, 1944, discloses esters of phthalic acid for stabilizing peroxides.
As can be seen from the foregoing, there is a continuing search for methods of preparing stable, liquid peroxyacid bleaches. It has now been discovered that by combining certain alcohols and certain acetate compounds in a ternary solvent system with a peroxyacid compound, a stabilizing agent and, optionally, a buffering agent, improved, stable bleaching compositions especially adapted to bleaching clothes during a laundering or rinsing operation are provided.
Accordingly, it is a primary object of the present invention to provide organic solvent/peroxyacid bleach compositions which are stable to decomposition on prolonged storage.
It is another object of the present invention to provide storage-stable concentrated peroxyacid bleaching compositions for use alone or in conjunction with other conventional cleaning compositions to enhance the cleansing of fabrics and clothing.
These and other objects are obtained herein as will be seen from the following disclosure.